Delta DVP12SE PLCs exposed via unauthenticated Modbus

Delta Electronics DVP12SE PLCs suffer from missing authentication on Modbus TCP and resource exhaustion flaws, allowing remote command execution and DoS across all versions.

CISA disclosed two vulnerabilities in Delta Electronics DVP12SE programmable logic controllers affecting all versions deployed worldwide in critical manufacturing environments. CVE-2026-12819 exposes an unauthenticated Modbus TCP service on the default port, permitting any network-reachable attacker to read and write coils, holding registers, relay states, and process control functions without credentials or privilege validation. CVE-2026-12818 is a resource allocation flaw allowing attackers to flood the Modbus port with raw or malformed packets, causing denial of service.

Delta Electronics is developing patches but currently recommends workarounds: enable the built-in IP filter to whitelist trusted HMI and SCADA hosts, configure password protection for control logic, and isolate PLCs in dedicated OT networks behind firewalls with VPN-only remote access. The vulnerabilities were reported by Adm Bin Harbi and Corvo Security. No active exploitation has been reported to CISA at publication.

The missing authentication flaw is particularly severe for internet-exposed or poorly segmented PLCs, as it grants full operational control to unauthenticated actors. Organizations using Delta DVP12SE controllers should immediately verify network isolation, implement IP filtering, and audit for any direct internet connectivity or flat IT/OT network architectures.

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-26-181-07